feat(gateway): API Key 인증 + HTTPS (Caddy) 보안 강화

- gateway.py: auth middleware — /api/* 엔드포인트에 Bearer token 필수
- Caddyfile: Let's Encrypt 자동 HTTPS 리버스 프록시
- docker-compose.yml: Caddy 추가, Gateway 포트 내부 전용
- config.py: GATEWAY_API_KEY 설정 추가
- .env: 키 생성 명령어 가이드 포함

Caddyfile

@@ -0,0 +1,9 @@
+# Gravity Gateway — Caddy Reverse Proxy
+# Automatic HTTPS via Let's Encrypt
+#
+# 도메인을 실제 도메인으로 변경하세요 (예: gateway.variet.net)
+# Caddy가 자동으로 Let's Encrypt 인증서를 발급합니다.
+
+gateway.variet.net {
+    reverse_proxy gateway:8585
+}

config.py

@@ -43,6 +43,7 @@ class Config:
     # Bot mode: 'local' (file-based bridge) or 'remote' (HTTP polling — future)
     BOT_MODE: str = os.getenv("BOT_MODE", "local")
     REMOTE_BRIDGE_URL: str = os.getenv("REMOTE_BRIDGE_URL", "")
+    GATEWAY_API_KEY: str = os.getenv("GATEWAY_API_KEY", "")
 
     @classmethod
     def validate(cls) -> list[str]:

docker-compose.yml

@@ -3,14 +3,15 @@ services:
     build: .
     container_name: gravity-gateway
     restart: unless-stopped
-    ports:
-      - "8585:8585"
+    # Port NOT exposed directly — Caddy handles external access
+    expose:
+      - "8585"
     environment:
       - DISCORD_TOKEN=${DISCORD_TOKEN}
       - DISCORD_GUILD_ID=${DISCORD_GUILD_ID}
       - BOT_MODE=gateway
       - GATEWAY_PORT=8585
-      # Brain path inside container (not used in gateway mode, but needed for config validation)
+      - GATEWAY_API_KEY=${GATEWAY_API_KEY}
       - BRAIN_PATH=/app/data/brain
     volumes:
       - gateway-data:/app/data
@@ -20,5 +21,21 @@ services:
         max-size: "10m"
         max-file: "3"
 
+  caddy:
+    image: caddy:2-alpine
+    container_name: gravity-caddy
+    restart: unless-stopped
+    ports:
+      - "443:443"
+      - "80:80"
+    volumes:
+      - ./Caddyfile:/etc/caddy/Caddyfile:ro
+      - caddy-data:/data
+      - caddy-config:/config
+    depends_on:
+      - gateway
+
 volumes:
   gateway-data:
+  caddy-data:
+  caddy-config:

gateway.py

@@ -28,11 +28,12 @@ logger = logging.getLogger(__name__)
 class GatewayAPI:
     """HTTP API server for Collector ↔ Gateway communication."""
 
-    def __init__(self, bot, host: str = "0.0.0.0", port: int = 8585):
+    def __init__(self, bot, host: str = "0.0.0.0", port: int = 8585, api_key: str = ""):
         self.bot = bot
         self.host = host
         self.port = port
-        self.app = web.Application()
+        self.api_key = api_key
+        self.app = web.Application(middlewares=[self._auth_middleware])
         self._setup_routes()
 
         # In-memory stores (Gateway is stateless across restarts)
@@ -47,6 +48,27 @@ class GatewayAPI:
         self.app.router.add_post("/api/register", self._post_register)
         self.app.router.add_get("/api/commands/{project}", self._get_commands)
 
+    # ─── Auth Middleware ───
+
+    @web.middleware
+    async def _auth_middleware(self, request: web.Request, handler):
+        """Reject requests without valid API key on /api/* routes."""
+        # Health endpoint is public
+        if request.path == "/health":
+            return await handler(request)
+
+        # All /api/* routes require auth
+        if request.path.startswith("/api/") and self.api_key:
+            auth = request.headers.get("Authorization", "")
+            if auth != f"Bearer {self.api_key}":
+                logger.warning(f"[GATEWAY] 401 Unauthorized: {request.method} {request.path} from {request.remote}")
+                return web.json_response(
+                    {"error": "Unauthorized", "detail": "Invalid or missing API key"},
+                    status=401,
+                )
+
+        return await handler(request)
+
     # ─── Health ───
 
     async def _health(self, request: web.Request) -> web.Response:
@@ -170,4 +192,5 @@ class GatewayAPI:
         await runner.setup()
         site = web.TCPSite(runner, self.host, self.port)
         await site.start()
-        logger.info(f"[GATEWAY] HTTP API started on {self.host}:{self.port}")
+        auth_status = "API Key enabled" if self.api_key else "⚠️ NO AUTH (set GATEWAY_API_KEY!)"
+        logger.info(f"[GATEWAY] HTTP API started on {self.host}:{self.port} [{auth_status}]")

main.py

@@ -84,7 +84,7 @@ async def main():
         if Config.BOT_MODE == 'gateway':
             from gateway import GatewayAPI
             gateway_port = int(os.environ.get('GATEWAY_PORT', '8585'))
-            gateway = GatewayAPI(bot, port=gateway_port)
+            gateway = GatewayAPI(bot, port=gateway_port, api_key=Config.GATEWAY_API_KEY)
             await gateway.start()
             logger.info(f"Gateway API running on port {gateway_port}")